No. A power of attorney creates a legal relationship fully called an attorney-at-fact, which is different from an attorney-at-law. An attorney-at-fact is an agent who is vested with powers (depending on the instrument creating the relationship) that allows an agent to act at the direction and in the stead of his or her principal to manage financial affairs or medical decisions when the principal is disabled from engaging in such functions due to absence, incompetence, etc. An attorney-at-fact does not have the powers of an attorney-at-law and this includes providing legal representation in a court of law.
While the U.S. Supreme Court has recognized that a person has a right to legal counsel and conversely the right to represent themselves (pro se), the Court has specifically and soundly rejected any argument that a person has a constitutional right to be represented by a third-party who is not a lawyer licensed to practice law.
If your son is unable to afford counsel on is own, he may be able to get court-appointed counsel. Alternatively, if you, your husband, and your son understand that a retained lawyer's duty and obligations run to your son and not you or your husband, even if you're paying the attorney's bill, then you can agree to pay for your son's retained attorney. Just understand that paying for the attorney gives you no control over the representation, nor no right to know what your son tells the attorney and vice versa.
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